I have a Service port on my Westinghouse 26" LCD TV.. It looks exactly like a USB port, but it is the flat port, instead of the square port needed to interface to a computer. Is there a cable that I could get to be able to plug into this port? I am interested to see if I can send codes to the TV to power it on and off (at the very least, hopefully it exposes as a serial driver that I can throw commands to.)

I have a 42 inch westinghouse model and contacted the company asking the very same thing. The official stance is that the USB port is for firmware upgrade. ( Which I have finished..it solved a locking issue) and NOTHING else is to be plugged into that port. Now customer service has been known to be inaccurate so you can give it a shot at your own risk and report back if your really curious.

Its for firmware updates and I don't actually think it will do anything else. If you're really curious I'd head over to the AVS forums and ask the Westinghouse owners on the LCD forums. They've probably done extensive testing of some kind and will probably be able to tell you if it can do anything except accept new firmware.